Color filter array having a blue filter layer

ABSTRACT

A color filter array having a blue filter layer on a substrate wherein the blue filter layer comprises triallylmethane dye showing its absorption maximum at a wavelength within the range of from 550 to 650 nm; and has a transmittance at a wavelength of 450 nm of 70% or more and that at 650 nm of 5% or less is provided; and the color filter array shows excellent spectroscopic characteristics with respect to blue light and has a blue filter layer excellent in light fastness.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to color filter arrays forsolid-state image devices or liquid crystal display devices, and to amethod for producing the same.

[0002] As a color filter array formed on a device such as a solid-stateimage device or a liquid crystal display device, there has been known acolor filter array (2) constituted of a red filter layer (R), a greenfilter layer (G), and a blue filter layer (B) formed so as to beadjoining to each other in the same plane of a substrate (1) (FIG. 1).In the color filter array (2), the filter layers (R), (G), (B) arearranged in a striped pattern (FIG. 2) or a lattice-like pattern(mosaic) (FIG. 3).

[0003] A variety of processes for producing such color filter array havebeen proposed. Among them, so-called “color resist method” is in widepractical use. In the color resist method, the patterning is effected byexposing a photosensitive resin composition comprising colorants tolight and developing, and the patterning is repeated in sequence in therequired times.

[0004] As the photosensitive resin composition which is employed in thecolor resist method, those employing pigments as colorants are in wideuse. However, such pigments are not suitable for the formation of fineor minute patterns, for they are granular and do not dissolve indevelopers, and developing residue is generated.

[0005] As a photosensitive resin composition for obtaining a finelypatterned color filter array, a photosensitive resin compositionemploying dyes as colorants has also been known. For example, JapanesePatent Application Laid-Open No. 6-75375 discloses a negativephotosensitive resin composition comprising dyes, and Japanese PatentPublication No. 7-111485 discloses a positive photosensitive resincomposition comprising 10 to 50%, on a dry weight basis, of a dyesoluble in the solvent used in the positive photosensitive resincomposition. (Hereinafter, “JP-A-” is used for indicating JapanesePatent Application Laid-Open, and “JP-B-” is used for indicatingJapanese Patent Publication.) Colorants comprised in photosensitiveresin compositions used for producing color filter arrays, such as thosedescribed above, are required to have the following two properties.

[0006] (1) Good spectroscopic characteristics, that is, showingsufficient absorption within the predetermined visible ray region and nounnecessary absorption in the other region.

[0007] (2) Good light fastness, that is, no burn-in due to thedecolorization of dyes under normal operating conditions However, noneof the dyes employed in conventional photosensitive resin compositionsused for forming a blue filter layer has both of the above-described twoproperties.

[0008] The inventors of the present invention have made intensive andextensive studies to develop a color filter array having a blue filterlayer having good spectroscopic characteristics as well as good lightfastness. As a result, they have found that the use of a specific dyerealizes the formation of a blue filter layer satisfactory both inspectroscopic properties and light fastness. The present invention wasaccomplished based on this finding.

SUMMARY OF THE INVENTION

[0009] The present invention provides a color filter array having a bluefilter layer on a substrate wherein the blue filter layer comprises atriallylmethane dye (hereinafter, referred to as “dye (I)”) showing itsabsorption maximum at a wavelength within the range of from 550 to 650nm; and has a transmittance at a wavelength of 450 nm of 70% or more andthat at 650 nm of 5% or less.

[0010] The present invention also provides a process for producing thecolor filter array.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] [FIG. 1]

[0012]FIG. 1 is a schematic view showing a cross-section of a colorfilter array in which a green filter layer, a red filter layer, and ablue filter layer are provided in the same plane of a substrate.

[0013] [FIG. 2]

[0014]FIG. 2 is a plane schematic view of a color filter array providedwith a green filter layer, a red filter layer, and a blue filter layerarranged in a striped pattern.

[0015] [FIG. 3]

[0016]FIG. 3 is a plane schematic view of a color filter array providedwith a green filter layer, a red filter layer, and a blue filter layerarranged in a mosaic pattern.

[0017] [FIG. 4]

[0018]FIG. 4 is a plane schematic view of the color filter arrayobtained in Example 1.

[0019] [FIG. 5]

[0020]FIG. 5 is a plane schematic view of the color filter arrayobtained in Example 1.

[0021] [FIG. 6]

[0022]FIG. 6 is a schematic view illustrating the steps in Example 5.

DESCRIPTION OF REFERENCE NUMERALS

[0023] 1: substrate

[0024] 2: color filter array

[0025] 3: over coating film

[0026] 4: polysilicon electrode

[0027] 5: sensor

[0028] 6: V resistor

[0029] 7: light-shielding film

[0030] 8: passivation film

[0031] 9: microlens

[0032] R: red filter layer

[0033] G: green filter layer

[0034] B: blue filter layer

[0035] Embodiment of the Invention

[0036] As the substrate used in the color filter of the presentinvention, a silicon wafer and a transparent inorganic glass plate areexemplified. On the silicone wafer, a charge coupled device may beformed.

[0037] The color filter array of the present invention has a blue filterlayer on its substrate.

[0038] Examples of the dye (I) include compounds represented by thegeneral formula (I):

[0039] wherein R¹⁰ and R¹¹ each independently represents hydrogen atomor an alkyl group having 1 to 3 carbon atoms; R¹² represents hydrogenatom or a sulfonic acid group; and R¹³ represents hydrogen atom,sulfonic acid group, a carboxylic acid group, an alkyl group having 1 to3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, or a grouprepresented by the general formula (1):

—NR¹⁴R¹⁵  (1)

[0040] wherein R¹⁴ and R¹⁵ each independently represents hydrogen atom,phenyl group, an alkyl group having 1 to 3 carbon atoms, or a phenylgroup substituted at the p-position with an alkoxyl group having 1 to 3carbon atoms; and salts thereof.

[0041] In a compound represented by the general formula (I), examples ofthe alkyl group having 1 to 3 carbon atoms represented by R¹⁰, R¹¹, R¹³,R¹⁴, or R¹⁵ include methyl group, ethyl group, and propyl group.Examples of the alkoxyl group having 1 to 3 carbon atoms represented byR¹³ include methoxy group, ethoxy group, and propoxy group. Examples ofthe phenyl group substituted at the p-position with an alkoxyl grouphaving 1 to 3 carbon atoms and represented by R¹⁴ or R¹⁵ includep-methoxyphenyl group, p-ethoxyphenyl group, and p-propoxyphenyl group.

[0042] The dye (I) maybe a compound represented by the general formula(I) or its salt. Examples of the salt are those with alkaline metalssuch as sodium and potassium or with amines such as triethylamine,2-ethylhexylamine and 1-amino-3-phenylbutane. The salt may be formed atthe position of —SO₃— residue or at an acid group represented by R¹² orR¹³ Examples of the dye (I) include C.I. Acid Blue 7, C.I. Acid Blue 83,C.I. Acid Blue 90, C.I. Solvent Blue 38, C.I. Acid Violet 17, C.I. AcidViolet 49 and C.I. Acid Green 3. These dyes (I) are used singly or incombination. These dyes (I) have their absorption maximum at awavelength within the range of from 550 to 650 nm.

[0043] The dye (I) can be dissolved in the photosensitive resincomposition at a high concentration. As a result, a blue filter layerhaving sufficient spectroscopic characteristics can be obtained by usingthe same, even when the filter layer has small thickness.

[0044] The amount of the dye (I) comprised therein is controlled so thattransmittance of the filter is 70% or more at a wavelength of 450 nm and5% or less at 650 nm.

[0045] For improving light fastness and controlling the color, that is,control of its spectroscopic characteristics, other dyes may beincorporated into the blue filter layer. For example, the blue filterlayer may comprise a copper phthalocyanine dye (hereinafter, referred toas “dye (II)”) having its absorption maximum at a wavelength of 600 to700 nm.

[0046] Examples of the dye (II) include compounds represented by thegeneral formula (II):

[0047] wherein R²⁰, R²¹, R²² and R²³ each independently represents asulfonic acid group, a sulfonamide group, or a sulfamoyl grouprepresented by the general formula (2):

R²⁴HN—SO₂—  (2)

[0048] wherein R²⁴represents an alkyl group having 2 to 20 carbon atoms,a cyclohexylalkyl group wherein the alkyl chain has 2 to 12 carbonatoms, an alkylcyclohexyl group wheein the alkyl chain has 1 to 4 carbonatoms, an alkyl group which has 2 to 12 carbon atoms and has beensubstituted with an alkoxyl group having 2 to 12 carbon atoms, analkylcarboxylalkyl group represented by the general formula (2-1):

R²⁵—CO—O—R²⁶—  (2-1)

[0049] wherein R²⁵ represents an alkyl group having 2 to 12 carbonatoms, and R²⁶ represents an alkylene group having 2 to 12 carbon atoms,

[0050] an alkyloxycarbonylalkyl group represented by the general formula(2-2):

R²⁷—O—CO—R²⁸—  (2-2)

[0051] wherein R²⁷ represents an alkyl group having 2 to 12 carbonatoms, and R²⁸ represents an alkylene group having 2 to 12 carbon atoms,

[0052] a phenyl group substituted with an alkyl group having 1 to 20carbon atoms, or an alkyl group which has 1 to 20 carbon atoms and hasbeen substituted with phenyl group; and

[0053] each of i, j, k, m independently represents an integer of 0 to 2with the proviso that i+j+k+m≦4; and salts thereof. Incorporation of thedye (II) improves the light fastness of the blue filter layer, that is,the ability of preventing so-called “burn-in” due to the decolorizationof dyes under normal operating conditions.

[0054] Examples of the alkyl group having 2 to 20 carbon atomsrepresented by R²⁴in the general formula (II) include ethyl group,propyl group, n-hexyl group, n-nonyl group, n-decyl group, n-dodecylgroup, 2-ethylhexyl group, 1,3-dimethylbutyl group, 1-methylbutyl group,1,5-dimethylhexyl group, and 1,1,3,3-tetramethylbutyl group. Examples ofthe cyclohexylalkyl group wherein the alkyl chain has 2 to 12 carbonatoms include cyclohexylethyl group, 3-cyclohexylpropyl group, and8-cyclohexyloctyl group. Examples of the alkylcyclohexyl group whereinthe alkyl chain 1 to 4 carbon atoms include 2-ethylcyclohexyl group,2-propylcyclohexyl group, and 2-(n-butyl)cyclohexyl group. Examples ofthe C₂₋₁₂ alkyl group substituted with an alkoxyl group having 2 to 12carbon atoms include 3-ethoxy-n-propyl group, propoxypropyl group,4-propoxy-n-butyl group, 3-methyl-n-hexyloxyethyl group, and3-(2-ethylhexyloxy)propyl group. Examples of the phenyl groupsubstituted with an alkyl group having 1 to 20carbon atoms includeo-isopropylphenyl group. Examples of the C₁₋₂₀ alkyl group substitutedwith phenyl group include DL-1-phenylethyl group, benzyl group, and3-phenyl-n-butyl group.

[0055] Examples of the alkyl group having 2 to 12 carbon atomsrepresented by R²⁵ in the general formula (2-1) and R²⁷ in the generalformula (2-2) include ethyl group, propyl group, n-hexyl group, n-nonylgroup, n-decyl group, n-dodecyl group, 2-ethylhexyl group,1,3-dimethylbutyl group, 1-methylbutyl group, 1,5-dimethylhexyl group,and 1,1,3,3-tetramethylbutyl group. Examples of the C₂₋₁₂ alkylene grouprepresented by R²⁶or R²⁸ include dimethylene group, trimethylene group,tetramethylene group, pentamethylene group and hexamethylene group.

[0056] The dye (II) may be a compound represented by the general formula(II) or salt thereof. Examples of the salt include those with alkalinemetals such as sodium and potassium or with amines such astrimethylamine, 2-ethylhexylamine, and 1-amino-3-phenylbutane. When thegroups R²⁰, R²¹, R²², or R²³ is a sulfonic acid group, the salt is onethat is formed at the position of the sulfonic acid group.

[0057] Examples of the dye (II) include C.I. Solvent Blue 25, C.I.Solvent Blue 55, C.I. Solvent Blue 67, C.I. Acid Blue 249, and C.I.Direct Blue 86. These are used singly or in combination. These dyes (II)have their absorption maximum at a wavelength within the range of from600 to 700 nm.

[0058] When the dye (II) is used, the amounts of the dye (II) comprisedin the blue filter is controlled so that transmittance of the filter is70% or more at a wavelength of 450 nm and 5% or less at 650 nm. Forexample, the content of a dye (I) per a total of 100 parts by weight ofthe dye (I) and the dye (II) is usually 30 to 70 parts by weight,preferably 40 to 60 parts by weight. When the content of the dye (I) isless than 30 parts by weight, the spectroscopic characteristics to bluelight tends to be insufficient. When the content of the dye (I) exceeds70 parts by weight, the light fastness tends to be insufficient.

[0059] The blue filter layer may further comprise a xanthene dye(hereinafter, referred to as “dye (III)”) having its absorption maximumat a wavelength of 500 to 600 nm.

[0060] Examples of the dye (III) include compounds represented by thegeneral formula (III):

[0061] wherein R³⁰, R³¹, R³², and R³³ each independently representshydrogen atom or an alkyl group having 1 to 3 carbon atoms; and R³⁴,R³⁵, and R³⁶ each independently represents a sulfonic acid group or agroup represented by the general formula (3):

R³⁷HNSO₂—  (3)

[0062] wherein R³⁷ represents an alkyl group having 2 to 20 carbonatoms, a cyclohexylalkyl group wherein the alkyl chain has 2 to 12carbon atoms, an alkylcyclohexyl group wherein the alkyl chain has 1 to4 carbon atoms, an alkyl group which has 2 to 12 carbon atoms and issubstituted with an alkoxyl group having 2 to 12 carbon atoms and, analkylcarboxylalkyl group represented by the general formula (3-1):

R³⁸⁰—CO—O—R³⁸¹  (3-1)

[0063] wherein R³⁸⁰ represents an alkyl group having 2 to 12 carbonatoms, and R³⁸¹represents an alkylene group having 2 to 12 carbon atoms,an alkyloxycarbonylalkyl group represented by the general formula (3-2):

R³⁹⁰—O—CO—R³⁹¹  (3-2)

[0064] wherein R³⁹⁰ represents an alkyl group having 2 to 12 carbonatoms, and R³⁹¹ represents an alkylene group having 2 to 12 carbonatoms,

[0065] a phenyl group substituted with an alkyl group having 1 to 20carbon atoms, or an alkyl group which has 1 to 20 carbon atoms and issubstituted with phenyl group; and salts thereof.

[0066] By incorporating the dye (III), the spectroscopic characteristicsof blue filter is controlled so that transmittance of the filter is 15%or less at a wavelength of 535 nm.

[0067] Examples of the alkyl group having 1 to 3 carbon atomsrepresented by R³⁰, R³¹, R³², or R³³ in the general formula (III)include methyl group, ethyl group, and propyl group. Examples of thealkyl group having 2 to 20 carbon atoms represented by R³⁷ are ethylgroup, propyl group, n-hexyl group, n-nonyl group, n-decyl group,n-dodecyl group, 2-ethylhexyl group, 1,3-dimethylbutyl group,1-methylbutyl group, 1,5-dimethylhexyl group, and1,1,3,3-tetramethylbutyl group. Examples of the cyclohexylalkyl groupwherein the alkyl chain has 2 to 12 carbon atoms include cyclohexylethylgroup, 3-cyclohexylpropyl group, and 8-cyclohexyloctyl group. Examplesof the alkylcyclohexyl group wherein the alkyl chain 1 to 4 carbon atomsinclude 2-ethylcyclohexyl group, 2-propylcyclohexyl group, and2-(n-butyl)cyclohexyl group. Examples of the C₂₋₁₂ alkyl groupsubstituted with an alkoxyl group having 2 to 12 carbon atoms include3-ethoxy-n-propyl group, propoxypropyl group, 4-propoxy-n-butyl group,3-methyl-n-hexyloxyethyl group, and 3-(2-ethylhexyloxy)propyl group.Examples of the phenyl group substituted with an alkyl group having 1 to20 carbon atoms include o-isopropylphenyl group. Examples of the C₁₋₂₀alkyl group substituted with phenyl group include DL-1-phenylethylgroup, benzyl group, and 3-phenyl-n-butyl group.

[0068] Examples of the alkyl group having 2 to 12 carbon atomsrepresented by R³⁸⁰ in the general formula (3-1) and R³⁹⁰ in the generalformula (3-2) include ethyl group, propyl group, n-hexyl group, n-nonylgroup, n-decyl group, n-dodecyl group, 2-ethylhexyl group,1,3-dimethylbutyl group, 1-methylbutyl group, 1,5-dimethylhexyl group,and 1,1,3,3-tetramethylbutyl group. Examples of the C₂₋₁₂ alkylene grouprepresented by R³⁸¹ or R³⁹¹ include dimethylene group, trimethylenegroup, tetramethylene group, pentamethylene group and hexamethylenegroup.

[0069] Examples of the dye (III) include C.I. Acid Red 289. These areused singly or in combination. These dyes (III) have their absorptionmaximum at a wavelength within the range of from 500 to 600 nm.

[0070] When the dye (III) is used, the amounts of the dye (III)comprised in the blue filter is controlled so that transmittance of thefilter is 15% or less at a wavelength of 535 nm. Concretely, the contentof a dye (III) per a total of 100 parts by weight of the dye (I) and thedye (II) is usually 70 parts by weight or less, preferably 15 to 50parts by weight. When the content of the dye (I) is less than 15 partsby weight, improvement of the spectroscopic characteristics becomesinsufficient and it tends to be difficult that transmittance of thefilter is 15% or less at a wavelength of 535 nm.

[0071] The color filter array of the present invention can be producedby an ordinary color resist method. For example, it can be produced by aprocess comprising the step of patterning a photosensitive resincomposition comprising colorants. The photosensitive resin compositioncomprises the dye (I). The amounts of the dye (I) comprised in thephotosensitive resin composition is the same as those in the desiredblue filter layer. If the blue filter layer is desired to comprise otherdyes, for example, the dye (II) and the dye (III), a photosensitiveresin composition comprising the dye (II) and the dye (III) is employed.The amounts of the dye (II) and the dye (III) comprised in thephotosensitive resin composition are the same as those in the desiredblue filter layer. The transmittance of the blue filter layer after thepatterning is 70% or more at 450 nm and 5% or less at 650 nm.

[0072] The photosensitive resin composition may be a positivephotosensitive resin composition or a negative photosensitive resincomposition.

[0073] The positive photosensitive resin composition of the presentinvention comprises, for example, a photoactive compound and analkali-soluble resin in addition to the above-described dyes.

[0074] A photoactive compound used in conventional photosensitive resincompositions can be used in the positive photosensitive resincomposition of the present invention. Examples thereof include esters ofphenolic compounds with o-naphthoquinonediazide sulfonates. Examples ofthe phenolic compounds include compounds represented by the chemicalformula (10).

[0075] As the o-naphthoquinonediazide sulfonates,o-naphthoquinonediazide-5-sulfonate ando-naphthoquinonediazide-4-sulfonate can be exemplified.

[0076] The term “alkali-soluble resin” refers to resins that dissolve inalkaline developers, and any alkali-soluble resin similar to those usedin conventional photosensitive resin compositions can be employed.Examples of such alkali-soluble resins include novolak resins such asthose of p-cresol novolak resins, novolak resins of p-cresol andm-cresol; novolak resins having the structure represented by the formula(20):

[0077] ; polyvinylphenol; and copolymers of styrene with vinylphenol.Preferably, a novolak resin is employed as the alkali-soluble resin.

[0078] The amounts of the dyes, the photoactive compound, and thealkali-soluble resin comprised in the photosensitive resin compositionare usually 10 to 50 parts by weight, 10 to 50 parts by weight and 3 to80 parts by weight, per a total of 100 parts by weight of the dyes,photoactive compound, and alkali-soluble resin, respectively.

[0079] Into the positive photosensitive resin composition, a curingagent may be incorporated. Incorporation of the curing agent improvesthe mechanical strength of the pattern formed by using thephotosensitive resin composition.

[0080] As the curing agent, usually, a heat curing agent which is curedthrough heating is employed. Examples of the heat curing agent includecompounds represented by the general formula (30):

[0081] wherein Q¹, Q², Q³, and Q⁴ each independently represents hydrogenatom, a hydroxyalkyl group having 1 to 4 carbon atoms, or an alkyl grouphaving 1 to 4 carbon atoms and substituted with an alkoxyl group having1 to 4 carbon atoms; Z represents phenyl group or a group represented bythe general formula (31):

Q⁵Q⁶N— (31)

[0082] wherein Q⁵ and Q⁶ each independently represents hydrogen atom, ahydroxyalkyl group having 1 to 4 carbon atoms, or an alkyl group having1 to 4 carbon atoms and substituted with an alkoxyl group having 1 to 4carbon atoms

[0083] with the proviso that at least one of Q¹ to Q⁶ is a hydroxyalkylgroup having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbonatoms and substituted with an alkoxyl group having 1 to 4 carbon atoms.

[0084] Examples of the hydroxyalkyl group having 1 to 4 carbon atomsinclude hydoxymethyl group, hydroxyethyl group, hydroxypropyl group, andhydroxybutyl group. Examples of the alkyl group having 1 to 4 carbonatoms and substituted with an alkoxyl group having 1 to 4 carbon atomsinclude methoxymethyl group, methoxyethyl group, ethoxyethyl group, andpropoxybutyl group.

[0085] An example of the compound represented by the general formula(30) is hexamethoxymethylmelamine.

[0086] Moreover, compounds of the following chemical formulae (32) to(37) can be used as the curing agent in the positive photosensitiveresin composition of the present invention, for example.

[0087] When the curing agent is used, its content is usually not lessthan 10 parts by weight and not more than 35 parts by weight per a totalof 100 parts by weight of the dyes, the photoactive compound, and thealkali-soluble resin.

[0088] The positive photosensitive resin composition of the presentinvention is usually diluted with a solvent.

[0089] The solvent is suitably selected according to the solubilities ofthe dye (I), dye (II), dye (III), photoactive compound, alkali-solubleresin, and curing agent, especially according to the solubilities of thedye (I), dye (II) and dye (III). For example, methyl cellosolve, ethylcellosolve, methyl cellosolve acetate, ethyl cellosolve acetate,diethylene glycol dimethyl ether, ethylene glycol monoisopropyl ether,propylene glycol monomethyl ether, N-methylpyrrolidone, γ-butyrolactone,dimethyl sulfoxide, N,N′-dimethylformamide, cyclohexane, ethyl acetate,n-butyl acetate, propylene glycolmonoethyl ether acetate, ethyl acetate,ethyl pyruvate, ethyl lactate, or the like can be employed. Thesesolvents are used either singly or in combination.

[0090] The amount of the solvent to be used is usually about 180 to 400parts by weight per a total of 100 parts by weight of the dyes,photoactive compound, alkali-soluble resin, and curing agent.

[0091] The negative photosensitive resin composition of the presentinvention comprises, for example, a photoreactive acid generator, acuring agent, and an alkali-soluble resin, in addition to the dyesdescribed above.

[0092] A photoreactive acid generator use in conventional negativephotoreactive resin compositions can be employed as the photoreactiveacid generator used in the negative photosensitive resin composition ofthe present invention. Examples thereof include compounds represented bythe general formula (40):

[0093] wherein Q⁷ represents an alkyl group having 1 to 3 carbon atoms,and Q⁸ represents a phenyl group substituted with an alkyl group having1 to 3 carbon atoms or a phenyl group substituted with an alkoxyl grouphaving 1 to 3 carbon atoms.

[0094] Examples of the alkyl group having 1 to 3 carbon atomsrepresented by Q⁷ include methyl group, ethyl group, and propyl group.An example of the phenyl group substituted with an alkyl group having 1to 3 carbon atoms and represented by Q⁸ is o-isopropylphenyl group.Examples of the phenyl group substituted with an alkoxyl group having 1to 3 carbon atoms include p-methoxyphenyl group, p-ethoxylphenyl group,and p-propoxyphenyl group.

[0095] Moreover, compounds represented by the chemical formulae (41) to(47):

[0096] can also be used as the photo acid generator, for example.

[0097] As the curing agent, a heat curing agent which is cured throughheating is usually employed as in the case of conventional negativephotosensitive resin composition. The heat curing agents listed above asexamples for the positive photosensitive resin composition can also beemployed in the negative photosensitive resin composition of the presentinvention.

[0098] The alkali-soluble resins listed above as examples for thepositive photosensitive resin composition can also be employed in thenegative photosensitive resin composition of the present invention, asin the case of conventional negative photosensitive resin composition.

[0099] The amounts of the photo acid generator, curing agent, andalkali-soluble resin comprised in the negative photosensitive resincomposition per a total of 100 parts by weight of the dyes,photoreactive acid generator, curing agent, and alkali-soluble resin areas follow. The content of the dyes is usually about 15 to 40 parts byweight, and that of the photo acid generator is usually 0.3 to 5 partsby weight. The amount of the curing agent to be used is usually 10 to 25parts by weight, and the content of the alkali-soluble resin is usually20 to 75 parts by weight.

[0100] The negative photosensitive resin composition is usually dilutedwith a solvent.

[0101] The solvent is selected according to the solubilities of the dye(I), dye (II), dye (III), photo acid generator, alkali-soluble resin,and curing agent, especially according to the solubilities of the dye(I), dye (II) and dye (III). The solvent listed above as examples forthe positive photosensitive resin composition can be employed. Theamount of the solvent to be used is usually about 180 to 400 parts byweight per a total of 100 parts by weight of the dyes, photo acidgenerator, curing agent, and alkali-soluble resin.

[0102] Since the above-described photosensitive resin compositionemploys the dye (I) and the dye (II) as its colorants, almost noprecipitate is generated even if the composition is stored for a longperiod of time. Consequently, the composition can be applied onto thesubstrate practically without irregularities. This makes it possible toprovide a color filter array having a blue filter layer with a patternof about 0.5 to 2 μm in thickness and about 2 to 20 μm in length of eachside.

[0103] The patterning is effected, for example, by providing a coat ofthe above-described resin composition on a substrate, exposing the coatto light, and then developing.

[0104] The coat is provided on the substrate by applying a dilutedphotosensitive resin composition thereto. The composition is usuallyapplied by spin coating. After the composition has been applied onto thesubstrate, the coat is heated up to, for example, about 80 to 130° C. toevaporate the solvent comprised therein. Thus, a coat of thephotosensitive resin composition is obtained.

[0105] Thereafter, the coat is exposed to light. The exposure to lightinvolves the use of a mask pattern corresponding to the desired pattern,and is effected by irradiating the coat with a beam through the maskpattern. As the beam for the exposure of the coat to light, for example,g-ray, i-ray, or the like can be employed. Such an exposure equipment asthe g-ray stepper or i-ray stepper may be employed for the exposure.When a negative photosensitive resin composition is used, the coat isheated after the exposure to light. When the positive photosensitiveresin composition is used, the coat may be heated after the exposure ormay not be heated. On heating the coat, the heating temperature is, forexample, about 80 to 150° C.

[0106] After having been exposed to light, the coat is subjected todevelopment. The development is effected by immersing the substrateprovided with the coat in a developer, as in the case of the use of anordinary photosensitive resin composition. Developer used for patterningconducted by using a conventional photosensitive resin composition canalso be employed in patterning in the present invention. A color filterarray having a blue filter layer defined in the desired pattern can beobtained by taking the substrate out of the developer and then washingwith water to remove the developer.

[0107] When a positive photosensitive resin composition is used, afterhaving been washed with water, the substrate may be subjected toultraviolet ray irradiation. Irradiation of ultraviolet rays candecompose the remaining photoactive compound and prevent colorationcaused by the remaining photoactive compound. Moreover, when thephotosensitive resin composition comprises a heat curing agent, thesubstrate may be heated after having been washed with water. By heating,the mechanical strength of the formed blue filter layer can be improved.The heating temperature is usually not lower than 160° C. and not higherthan 220° C. Usually, the heating temperature is not higher than thedecomposition temperatures of the dyes.

[0108] When a negative photosensitive resin composition is used, thesubstrate may be heated after having been washed with water. By heating,the mechanical strength of the formed blue filter layer is improved. Theheating temperature is usually not lower than 160° C. and not higherthan 220° C. Usually, the heating temperature is not higher than thedecomposition temperatures of the dyes.

[0109] Thus, a blue filter layer in the desired pattern is formed. Theother filter layers, that is, a red filter layer and a green filterlayer are formed in the same plane of the substrate which has beenprovided with the blue filter layer, according, for example, to aconventional manner. When employing a positive photosensitive resincomposition, it is preferred to employ one comprising a curing agent andcarry out heating after development, for the strength of the formed bluefilter layer is improved. The blue filter layer may be formed after theother color filter layers have been provided on the substrate.

[0110] Thus, a color filter array constituted of the red filter layer,green filter layer, and blue filter layer that are formed so as to beadjoining to each other in the same plane of the substrate can beobtained. The color filter array thus obtained is used for a solid-stateimage device, a liquid crystal display device, and the like. Forinstance, in the solid-state image device, if the color filter array isdisposed on the front side of its charge-coupled device, color imagesexcellent in color reproductivity, especially in the reproductivity ofblue color, can be obtained.

[0111] The color filter array of the present invention shows excellentspectroscopic characteristics with respect to blue light and has a bluefilter layer excellent in light fastness. Moreover, since dyes areemployed as its colorants, the photosensitive resin composition to beemployed for its production generates a less amount of precipitates andis excellent in store stability. As a result, a blue filter layer lessin foreign matter content, and uniform in thickness can be produced withease. This color filter array is favorably employed for use in a liquidcrystal display device or a solid-state image device comprising acharge-coupled device.

[0112] Hereinafter, the present invention will be described in moredetail based on Examples, but these should by no means be construed asdefining the scope of the present invention.

EXAMPLE 1

[0113] After 20 parts by weight of C.I. Acid Blue 83 as the dye (I), 10parts by weight of C.I. Solvent blue 67 as the dye (II), 10 parts byweight of the ester of a phenolic compound represented by the chemicalformula (10) with o-naphthoquinonediazide-5-sulfonate, as thephotoactive compound, 30 parts by weight of a novolak resin of p-cresolas the alkali-soluble resin (weight average molecular weight in terms ofpolystyrene: 5,000), 15 parts by weight of hexamethoxymethylmelamine asthe curing agent, and 300 parts by weight of ethyl lactate as thesolvent had been mixed and dissolved, the resulting mixture wasfiltrated with a membrane filter having a pore size of 0.1 μm to providea positive photosensitive resin composition.

[0114] A coat was formed by applying the positive photosensitive resincomposition obtained above onto a substrate (silicon wafer) by spincoating and heating at 100° C. for 1 minute to evaporate ethyl lactatetherefrom. The coat had been exposed to light by irradiation of i-raythrough a mask pattern using an exposure equipment (“Nikon NSR i7A”manufactured by Nikon Corp.). Then, the pattern was developed byimmersing the coated substrate in a developer (“SOPD” manufactured bySumitomo Chemical Co., Ltd.) at 23° C. for 1 minute. After thedevelopment, the substrate was washed with water, dried, irradiated withultraviolet rays, and heated to 180° C. for 3 minutes to give a colorfilter array having a blue filter layer in a striped-pattern (FIG. 4).The blue filter layer has a line width of 1.0 μm and a thickness of 1.5μm.

[0115] Thereafter, except using a different mask pattern, the sameprocedure as above was repeated to give a color filter array having ablue filter layer formed in a mosaic pattern (FIG. 5). The blue filterlayer has a line width of 2.0 μm and a thickness of 1.5 μm.

[0116] Except that a transparent glass plate was employed as thesubstrate in place of a silicon wafer and that the pattern was notexposed to light and not developed, the same procedure as above wasrepeated to give a blue filter layer formed in a thickness of 1.5 μm allover the substrate.

EXAMPLE 2

[0117] Except that C.I. Acid Blue 83 was replaced with 20 part by weightof C.I. Acid Blue 90 as the dye (I) and 3 part by weight of the compoundrepresented by the formula (52):

[0118] was used as the dye (III), the same procedure as in Example 1 wasrepeated to give a color filter array having a striped-pattern bluefilter layer with a line width of 1.0 μm and a thickness of 1.5 μm, acolor filter array having a mosaic-pattern blue filter layer with a linewidth of 2.0 μm and a thickness of 1.5 μm, and a blue filter layerformed in a thickness of 1.5 μm all over the substrate.

EXAMPLE 3

[0119] Except that 2 parts by weight of a compound represented 20 by thechemical formula (51):

[0120] as the photo acid generator is used in place of the photoactivecompound, the same procedure as in Example 1 was repeated to obtain anegative photosensitive resin composition.

[0121] A coat was formed by applying the negative photosensitive resincomposition obtained above onto a substrate (silicon wafer) by spincoating and heating at 100° C. for 1 minute to evaporate ethyl lactatetherefrom. The coat had been exposed to light by irradiation of i-raythrough a mask pattern using an exposure equipment (“Nikon NSR i7A”manufactured by Nikon Corp.), followed by heated at 120° C. for 1minute. Then, the pattern was developed by immersing the coatedsubstrate in a developer (“SOPD” manufactured by Sumitomo Chemical Co.,Ltd.) at 23° C. for 1 minute. After the development, the substrate waswashed with water, dried, irradiated with ultraviolet rays, and heatedto 180° C. for 3 minutes to give a color filter array having a bluefilter layer in a striped-pattern. The blue filter layer has a linewidth of 1.0 μm and a thickness of 1.5 μm.

[0122] Thereafter, except using a different mask pattern, the sameprocedure as in Example 1 was repeated to give a color filter arrayhaving a blue filter layer formed in a mosaic pattern. The blue filterlayer has a line width of 2.0 μm and a thickness of 1.5 μm.

[0123] Except that a transparent glass plate was employed as thesubstrate in place of a silicon wafer and that the exposure to light wasconducted without using the mask pattern, the same procedure as inExample 1 was repeated to give a blue filter layer formed in a thicknessof 1.8 Am all over the substrate.

EXAMPLE 4

[0124] Except that the dye (II) was not used and the amount of the dye(I) was changed to 50 parts by weight, the same procedure as in Example1 was repeated to give a color filter array having a striped-patternblue filter layer with a line width of 1.0 μm and a thickness of 1.5 μm,a color filter array having a mosaic-pattern blue filter layer with aline width of 2.0 μm and a thickness of 1.5 μm, and a blue filter layerformed in a thickness of 1.5 μm all over the substrate.

EXAMPLE 5

[0125] A photosensitive resin composition for forming a green filterlayer, a photosensitive resin composition for forming a red filterlayer, and a photosensitive resin composition for forming a blue filterlayer were prepared according to the respective blending formulationsshown below. (Photosensitive resin composition for forming a red filterlayer) Novolak resin 5 parts by weighto-naphthoquinonediazide-4-sulfonate 8 parts by weightHexamethoxymethylmelamine 2 parts by weight Ethyl lactate 50 parts byweight  N,N′-dimethylformamide 25 parts by weight  A compoundrepresented by the chemical 2 parts by weight formula (52) C.I. SolventOrange 56 2 parts by weight C.I. Solvent Yellow 82 2 parts by weightC.I. Solvent Yellow 162 2 parts by weight (Photosensitive resincomposition for forming a blue filter layer) Novolak resin 5 parts byweight o-naphthoquinonediazide-4-sulfonate ester 8 parts by weightHexamethoxymethylmelamine 2 parts by weight Ethyl lactate 50 parts byweight  N,N′-dimethylformamide 25 parts by weight  A compoundrepresented by the chemical 3 parts by weight formula (52) C.I. SolventBlue 25 3 parts by weight C.I. Acid Blue 90 2 parts by weight(Photosensitive resin composition for forming a green filter layer)Novolak resin 5 parts by weight o-naphthoquinonediazide-4-sulfonateester 8 parts by weight Hexamethoxymethylmelamine 2 parts by weightEthyl lactate 50 parts by weight  N,N′-dimethylformamide 25 parts byweight  C.I. Solvent Blue 25 4 parts by weight C.I. Solvent Yellow 82 2parts by weight C.I. Solvent Yellow 162 2 parts by weight

[0126] The photosensitive resin composition for forming a red filterlayer prepared above had been applied onto a silicon wafer provided witha charge-coupled device constituted of a over coating film (3), apolysilicon electrode (4), a sensor (5), a V resistor (6), alight-shielding film (7), and a passivation film (8) by spin coating.Then, its solvent was evaporated off on a baking plate at 100° C.

[0127] Thereafter, using an i-ray stepper exposure equipment (“NikonNSR2205 i12D” manufactured by Nikon Corp.), the substrate was irradiatedwith an ultraviolet ray of a wavelength of 365 nm through a reticle(2,000 mJ/cm²). Then, the substrate was subjected to development by adeveloping agent (an aqueous solution containing 30g oftetramethylammonium hydroxide per 1,000 cm³). After the exposed portionhad been removed, the substrate was washed with pure water. Thereafter,using a low-pressure mercury lamp (3,000 mJ/cm²), ultraviolet rays wereirradiated all over the substrate, and the substrate was then heated ona baking plate at 180° C. for 10 minutes to form a red filter layer(FIG. 6(a)).

[0128] Except for using the photosensitive resin composition for forminga blue filter layer prepared above instead of the photosensitive resincomposition for forming a red filter layer, the same procedure as abovewas repeated to form a blue filter layer (FIG. 6(b)).

[0129] Except for using the photosensitive resin composition for forminga green filter layer prepared above, the same procedure as above wasrepeated to form a green filter layer and consequently a color filterarray (FIG. 6(c), (d)).

[0130] A microlens was formed on the color filter array in aconventional manner to give a solid-state image device. The thickness ofthe blue filter layer of the color filter array at the solid-state imagedevice was 1.7 μm. The color filter array at this solid-state imagedevice showed good spectroscopic characteristics (FIG. 6(e)).

[0131] In the same manner as that described above, a blue filter layer(thickness: 1.7 μm) was formed all over a quartz wafer.

[0132] Evaluation

[0133] (1) Spectroscopic Characteristics

[0134] The color filter arrays each provided with a blue filter layerall over its substrate and obtained in Examples and Comparative Examplewere subjected to measurement of light transmittance at 450 nm, 535 nm,and 650 nm. The results are shown in Table 1.

[0135] (2) Light Fastness

[0136] An ultraviolet ray-blocking filter (“colored optical glass L38”manufactured by Hoya Corp. Capable of blocking light of a wavelength of380 nm or shorter) was disposed in front of each of the color filterarrays obtained in Examples and provided with a blue filter layer allover its substrate, followed by irradiating light at 1,000,000 1×·hour.“Sun tester XF 180 CPS” manufactured by Shimadzu Corp. was employed asthe light source. The light transmittance of each color filter arrayafter the irradiation was measured at a wavelength of 450 nm, 535 nm,and 650 nm. The results are shown in Table 2. TABLE 1 Lighttransmittance (%) Wavelength (nm) 450 535 650 Example 1 74 17 3.4Example 2 75 5 2.8 Example 3 72 18 1.8 Example 4 74 11 2.0

[0137] TABLE 2 Light transmittance (%) Wavelength (nm) 450 535 650Example 1 72 22 4.5 Example 2 72 6 4.0 Example 3 69 23 3.0 Example 4 6215 6.0

What is claimed is:
 1. The present invention provides a color filterarray having a blue filter layer on a substrate wherein the blue filterlayer comprises a triallylmethane dye showing its absorption maximum ata wavelength within the range of from 550 to 650 nm; and has atransmittance at a wavelength of 450 nm of 70% or more and that at 650nm of 5% or less.
 2. The color filter array having a blue filter layeron a substrate according to claim 1, wherein the blue filter layerfurther comprises a copper phthalocyanine dye having its absorptionmaximum at a wavelength of 600 to 700 nm.
 3. The color filter arrayhaving a blue filter layer on a substrate according to claim 1, whereinthe blue filter layer further comprises a xanthene dye having itsabsorption maximum at a wavelength of 500 to 600 nm, and has atransmittance of 15% or less at 535 nm.
 4. The color filter array havinga blue filter layer on a substrate according to claim 2, wherein theblue filter layer further comprises a xanthene dye having its absorptionmaximum at a wavelength of 500 to 600 nm, and has a transmittance of 15%or less at 535 nm.
 5. A process for producing a color filter arrayhaving a blue filter layer on a substrate which comprises the step ofpatterning a photosensitive resin composition comprising atriallylmethane dye showing its absorption maximum at a wavelengthwithin the range of from 550 to 650 nm; and has a transmittance at awavelength of 450 nm of 70% or more and that at 650 nm of 5% or less. 6.The process according to claim 5, wherein the photosensitive resincomposition further comprises a copper phthalocyanine dye having itsabsorption maximum at a wavelength of 600 to 700 nm.
 7. The processaccording to claim 5, wherein the photosensitive resin compositionfurther comprises a xanthene dye having its absorption maximum at awavelength of 500 to 600 nm, and the blue filter layer has atransmittance of 15% or less at 535 nm.
 8. The process according toclaim 6, wherein the photosensitive resin composition further comprisesa xanthene dye having its absorption maximum at a wavelength of 500 to600 nm, and the blue filter layer has a transmittance of 15% or less at535 nm.
 9. A photosensitive resin composition comprising atriallylmethane dye showing its absorption maximum at a wavelengthwithin the range of from 550 to 650 nm.
 10. A photosensitive resincomposition according to claim 9, which further comprises a copperphthalocyanine dye having its absorption maximum at a wavelength of 600to 700 nm.
 11. The photosensitive resin composition according to claim10, wherein the amount of the triallylmethane dye is 30 to 70 parts byweight per a total of 100 parts by weight of the triallylmethane dye andthe copper phthalocyanine dye.
 12. The photosensitive resin compositionaccording to claim 10 that further comprises a xanthene dye having itsabsorption maximum at a wavelength of 500 to 600 nm.
 13. Thephotosensitive resin composition according to claim 12, wherein theamount of the triallylmethane dye is 30 to 70 parts by weight and theamount of the xanthene dye is 70 parts by weight or less per a total of100 parts by weight of the copper phthalocyanine dye and the xanthenedye.
 14. The photosensitive resin composition according to claim 9 whichfurther comprises a photoactive compound, and an alkali-soluble resin,and wherein the amounts of the dyes, the photoactive compound, and thealkali-soluble resin are 10 to 50 parts by weight, 10 to 50 parts byweight, and 3 to 80 parts by weight, per a total of 100 parts by weightof the dyes, photoactive compound, and alkali-soluble resin,respectively.
 15. The photosensitive resin composition according toclaim 14 which further comprises a curing agent, and wherein the amountof the curing agent is not less than 10 parts by weight and not morethan 35 parts by weight per a total of 100 parts by weight of the dyes,the photoactive compound, and the alkali-soluble resin.
 16. Thephotosensitive resin composition according to claim 9 which furthercomprises photo acid generator, curing agent, and an alkali-solubleresin, and wherein the amounts of the dyes, the photo acid generator,the curing agent, and the alkali-soluble resin are about 15 to 40 partsby weight, 0.3 to 5 parts by weight, 10 to 25 parts by weight, and 20 to75 parts by weight, per a total of 100 parts by weight of the dyes,photoreactive acid generator, curing agent, and alkali-soluble resin,respectively.